What is the value of |a|/a+|b|/b?

Question

What is the value of  \frac{|a|}{a}+\frac{|b|}{b} ?
(1) ab<0
(2)  \frac{|a|}{a}=-\frac{|b|}{b}

New question

amanvermagmat · Answer

If a number x is positive, then |x| = x and thus |x|/x = 1
If a number y is negative, then |y| = -y and thus |y|/y = -1

(1) ab < 0 . This means out of a/b, one is negative and other is positive.
So one of |a|/a and |b|/b will be '1' and the other will be '-1'. So the sum will be '0'. Sufficient.

(2) |a|/a = -|b|/b
This means |a|/a + |b|/b = 0. Sufficient.

Hence  D answer

TaN1213 · Answer

Possible cases :
Case 1: -1 -1 = -2
Case 2: -1 +1 =0
Case 3: 1 +1 = 2 
Case 4: 1- 1 = 0

St. 1 says a and b have opposite signs. Cases 2 & 4. Both gives a sum of 0. 
Sufficient

St.2 directly gives the sum 0.
Sufficient

-D-

Mo2men · Answer

Great question chetan2u (2) \frac{|a|}{a}=-\frac{|b|}{b} Apply directly in the question \frac{|a|}{a}+\frac{|b|}{b} = -\frac{|b|}{b}+\frac{|b|}{b} = 0 Sufficient (1) ab<0 Here it means a & b have different sign Case 1: a > 0 & b < 0 : then |a| = a & |b| = -b. Therefore, \frac{a}{a}+\frac{-b}{b} = 1 -1 = 0 Case 1: a < 0 & b > 0 : then |a| = -a & |b| = b. Therefore, \frac{-a}{a}+\frac{b}{b} = -1 + 1 = 0 Sufficient Answer: D

bhargavasrikantha · Answer

Answer is (D)

(i) ab<0 means either a or b - ve. that implies., |a|/a + |b|/b = 0 using a -ve or b -ve. Sufficient. 
(ii) simplying equation, we can determine |a|/a + |b|/b = 0. Suffiient.

MathRevolution · Answer

Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution. The first step of the VA (Variable Approach) method is to modify the original condition and the question. We then recheck the question. |x|/x = 1 if x > 0 and |x|/x = -1 if x < 0. Condition 1) ab < 0 ⇔ a > 0, b < 0 or a < 0, b > 0 ⇔ |a|/a = 1, |b|/b = -1 or |a|/a = -1, |b|/b = 1 ⇔ |a|/a + |b|/b = 0 for both sides Thus the condition 1) is sufficient. Condition 2) |a|/a = -|b|/b ⇔ |a|/a + |b|/b = 0 Thus the condition 2) is sufficient. Therefore, D is the answer.

What is the value of |a|/a+|b|/b?

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